[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen stable-4.12] libxl: workaround gcc 10.2 maybe-uninitialized warning
commit fd4cc0bc9b362e11c28f8025b94fc548c5ffe2fe Author: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx> AuthorDate: Wed Aug 19 04:00:35 2020 +0200 Commit: Ian Jackson <iwj@xxxxxxxxxxxxxx> CommitDate: Mon Nov 9 17:58:13 2020 +0000 libxl: workaround gcc 10.2 maybe-uninitialized warning It seems xlu_pci_parse_bdf has a state machine that is too complex for gcc to understand. The build fails with: libxlu_pci.c: In function 'xlu_pci_parse_bdf': libxlu_pci.c:32:18: error: 'func' may be used uninitialized in this function [-Werror=maybe-uninitialized] 32 | pcidev->func = func; | ~~~~~~~~~~~~~^~~~~~ libxlu_pci.c:51:29: note: 'func' was declared here 51 | unsigned dom, bus, dev, func, vslot = 0; | ^~~~ libxlu_pci.c:31:17: error: 'dev' may be used uninitialized in this function [-Werror=maybe-uninitialized] 31 | pcidev->dev = dev; | ~~~~~~~~~~~~^~~~~ libxlu_pci.c:51:24: note: 'dev' was declared here 51 | unsigned dom, bus, dev, func, vslot = 0; | ^~~ libxlu_pci.c:30:17: error: 'bus' may be used uninitialized in this function [-Werror=maybe-uninitialized] 30 | pcidev->bus = bus; | ~~~~~~~~~~~~^~~~~ libxlu_pci.c:51:19: note: 'bus' was declared here 51 | unsigned dom, bus, dev, func, vslot = 0; | ^~~ libxlu_pci.c:29:20: error: 'dom' may be used uninitialized in this function [-Werror=maybe-uninitialized] 29 | pcidev->domain = domain; | ~~~~~~~~~~~~~~~^~~~~~~~ libxlu_pci.c:51:14: note: 'dom' was declared here 51 | unsigned dom, bus, dev, func, vslot = 0; | ^~~ cc1: all warnings being treated as errors Workaround it by setting the initial value to invalid value (0xffffffff) and then assert on each value being set. This way we mute the gcc warning, while still detecting bugs in the parse code. Signed-off-by: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx> Reviewed-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx> (cherry picked from commit d25cc3ec93ebda030349045d2c7fa14ffde07ed7) --- tools/libxl/libxlu_pci.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/tools/libxl/libxlu_pci.c b/tools/libxl/libxlu_pci.c index 2cd793d223..e39c2c7250 100644 --- a/tools/libxl/libxlu_pci.c +++ b/tools/libxl/libxlu_pci.c @@ -45,10 +45,11 @@ static int pcidev_struct_fill(libxl_device_pci *pcidev, unsigned int domain, #define STATE_TYPE 9 #define STATE_RDM_STRATEGY 10 #define STATE_RESERVE_POLICY 11 +#define INVALID 0xffffffff int xlu_pci_parse_bdf(XLU_Config *cfg, libxl_device_pci *pcidev, const char *str) { unsigned state = STATE_DOMAIN; - unsigned dom, bus, dev, func, vslot = 0; + unsigned dom = INVALID, bus = INVALID, dev = INVALID, func = INVALID, vslot = 0; char *buf2, *tok, *ptr, *end, *optkey = NULL; if ( NULL == (buf2 = ptr = strdup(str)) ) @@ -170,6 +171,8 @@ int xlu_pci_parse_bdf(XLU_Config *cfg, libxl_device_pci *pcidev, const char *str if ( tok != ptr || state != STATE_TERMINAL ) goto parse_error; + assert(dom != INVALID && bus != INVALID && dev != INVALID && func != INVALID); + /* Just a pretty way to fill in the values */ pcidev_struct_fill(pcidev, dom, bus, dev, func, vslot << 3); -- generated by git-patchbot for /home/xen/git/xen.git#stable-4.12
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